Fingerplay: Tickle a chimp with care

A. Probably yes, if you've got a dog or cat, though it's tough to identify the associated behavior because they lack "play vocalizations" as recognizable as ha-ha, says behavioral neuroscientist Robert Provine in Laughter: A Scientific Investigation. Got a pet squirrel?

"Outside my office window two young squirrels are at play– it's easy to imagine reciprocal tickling binds them during their lively wrestling and racing through the tree branches," akin to human "tickle battles" that sometimes wind up in sex. Young dogs, cats, and rats have similar escapades. Psychologist Jaak Panksepp has finger-tickled laboratory rats, prompting playful nips and ultrasonic chirps.

More in the family, chimpanzee researcher Roger Fouts, a teacher of sign language to Washoe, said tickling is so popular with chimps they engage in tickle-fests, and signers will even converse about it. "But chimps are remarkably strong and can easily injure their human playmates. Whether tickling chimpanzees, a 500-pound gorilla, or another human, it's important to have a consenting and friendly subject," Fouts says.

Q.Statistically and scientifically speaking, can prayer help treat medical conditions? What are some of the conundrums that make a "yes" or "no" here problematic? &shy;J. Falwell

A. No doubt religion can be a dramatic de-stressor, optimism booster, and enhancer of well-being that leads to health and longer life. But the difficulty with empirically testing prayer on sick people is that most of them already have others praying for them, says Hope College psychologist David G. Myers in &quot;Is Prayer Clinically Effective?" in Reformed Review. So how to test the effect of additional "controlled" prayers? "Does God follow a dose-response curve– more prayers, more response? Does God count votes?"

And whose prayers would count most? The sick person's? The family? Friends? Strangers who learn of the condition? If this were true, the rich could pay people to pray for them, using their money to petition heavenly advantage.

And, poses Myers, doesn't even just doing such an experiment reveal a doubting that calls into question true belief? For many reasons, the prayer proposition is probably not a testable one, and best taken on faith.

Q.The professor strips shirtless, then lies down sandwiched between two beds of nails and has a student stand on the sandwich. What's he trying to prove? &shy;A. Farrell

A. Cleveland State University physicist Jearl Walker, the meat in the sandwich on many occasions, says "there's no surer way to gain a class's attention than to give a demo in which the teacher may very well die." The principle involved is force vs. pressure– if the weight of the stander is spread over enough nails, the force on each nail will be insufficient to puncture the skin.

For an encore, an assistant places a concrete block on the top bed of nails and smashes it with a sledgehammer. Here the large mass of the cinder block prevents it from accelerating rapidly downward, and also it breaks, absorbing energy.

"I must caution that while the first demonstration is only eccentric, the second one is quite dangerous. I have been frequently gashed by the violent scatter of concrete chunks but have been lucky enough that my teeth and eyes have gone unharmed," he says.

A. Swallowed food is grabbed by the smooth muscle of the esophagus, which contracts in front of the bolus and relaxes behind it, thus moving it along toward the stomach, say J.B.S. Haldane et al. in Animal Biology. Owing to this involuntary action, one could as well ingest a meal while heels over head.

Q.Party trick: Hold a dollar hanging lengthwise between a friend's thumb and forefinger an inch apart half way down the bill. Suddenly, let go. Can she snap fingers shut fast enough to snag it and win the buck? &shy;U. Scrooge

A. Surprisingly, just about nobody can, says Paul Hewitt in Conceptual Physics. The dollar drops through in about 1/8th second, reflex time is typically 1/7th second, so she'll squeeze on only thin air.